Sites In Korea Research Articles

Field Performance of Refractory Softwoods Treated with CA or ACQ after 10 Years of Exposure in Korea and Canada

Abstract Korean wood preservation standards require deep penetration, which precludes the use of many refractory species. However, such treatments of refractory species have been shown to be effective in other parts of the world. A field test was therefore initiated to evaluate the performance of western hemlock, a moderately refractory species, and white spruce, a highly refractory species, pressure treated with either copper azole or alkaline copper quaternary under Korean field conditions that included both decay and termite hazards. After 10 years of exposure in a ground proximity and field stake test in Jinju, Korea, the treated materials remained largely sound, while untreated controls failed much earlier, largely due to termite attack. These data suggest that material that does not meet current Korean penetration requirements could still provide effective protection against biodegradation under Korean conditions. Decay was more advanced in matched treated stakes exposed at a test site in Canada than at the site in Korea.

Sexual dimorphism and sex-differential migration of Little Buntings (Emberiza pusilla) at an East Asian stopover site

Sex differences in morphology provide key information for understanding a species' morphological adaptations in relation to the evolution of sexual selection. In migratory birds, morphological traits have adapted to long-distance travel, and sexual dimorphism is typically related to sex-differential migration phenology. Little Buntings (Emberiza pusilla) have one of the longest migrations and are the least dichromatic species among the Emberiza buntings. In this study, we measured sexual size dimorphism and sexual dichromatism of Little Buntings in relation to the spring arrival dates at a stopover site in Korea. Wing length was the most important predictor for identifying sex; the wings of males were longer than those of females. Males also had a significantly stronger chestnut color of the head feathers than females, but this color difference was more prominent in the spring than in the fall. Males arrived earlier than females by four days. Arrival dates correlated with both size and color, but unlike other bunting species previously studied in the same area, there was no clear sex-differential trend in the relationship between arrival date and morphological characteristics. Seasonal differences in the degree of sexual dichromatism suggest that chestnut plumage coloration can be used as a social or sexual signal of males in the breeding season. The correlation of size and color to early arrival regardless of sex may indicate that a preference for assortative mating exists or that a sex-differential migration strategy is not clearly defined in the early stages of northward migration. Our findings on the sexual dimorphism of Little Buntings provide insight into the evolution of the sex-differential migration of buntings in the East Asian Flyway.

Analysis of Raindrop Size Distribution and Estimation of Cloud Microphysical Processes Using Ground-Based Observations at Mountain Sites in Korea and at Other Sites in the East Asian Region

Analysis of Raindrop Size Distribution and Estimation of Cloud Microphysical Processes Using Ground-Based Observations at Mountain Sites in Korea and at Other Sites in the East Asian Region

How did the introduction of stemmed points affect mobility and site occupation during the late Pleistocene in Korea?

We use models from human behavioral ecology to examine stone artifacts from 23 sites in Korea to investigate mobility and site occupation patterns during the Late Pleistocene. This is an important period because new tools, such as stemmed points and blades, appeared in the archaeological record. We focus on two questions: what changes in foragers’ landscape use were associated with the introduction of new tools? And what changes in mobility and the way people used habitation sites were associated with the new technology? To answer these questions we present quantitative analyses of artifact volumetric density, retouch frequency, composition of toolkits, and artifact raw materials. We explore environmental and demographic contexts by applying paleoclimate simulations and summed probability distribution models. We find that quartz and side scrapers, in addition to cores and choppers, remain dominant in assemblages before and after the introduction of stemmed points throughout the Late Pleistocene. Our results show that forager groups using stemmed points may have been associated with occupation of marginal or extreme environments. Groups with stemmed points were associated with expedient technologies, indicating residential and less mobile behaviors. The environmental context of this technological innovation was a gradual decrease in temperature into the LGM. Population increased before the appearance of stemmed points.

Implementation of an Uncontrolled, Real‐World Task: Vocabulary Learning Opportunities and Students’ Perceptions

AbstractTask‐based research has shown the benefits of using tasks in various instructional contexts across different age groups. Although task‐based language teaching promotes language learning through authentic real‐world tasks, previous research has mainly used controlled pedagogic tasks. The current exploratory, intact‐classroom, multi‐case study examined the extent to which 13 Korean adolescent learners of English used and learned new English lexical items while carrying out an uncontrolled, real‐world, multimodal, video‐creation task. It further investigated students’ perceptions of performing such a task. Target items included 93 English lexical items that appeared in realia at a historical site in Korea. The video‐creation task was carried out over 5 days and included pretask planning, a field trip to the Korean historical site, and creation of a travel guide video for the site in a computer lab. Students’ interactions were recorded digitally. Results revealed that the degree of target‐item production varied by participant, but overall target lexical items were not greatly used by students. Students’ perceptions of the benefits of the uncontrolled, real‐world task seemed to relate to task‐as‐process, which was directly influenced by learner‐generated workplans. Pedagogical implications for designing and implementing real‐world tasks requiring task performance inside and outside of the classroom are discussed.

An historical overview of the field of study of human remains in South Korean archaeology

AbstractThe purpose of this study is to present the current status of research into human remains excavated from archaeological sites in South Korea following its liberation from Japanese colonial rule and to examine the improvements potentially needed to conduct adequate archaeological research on human remains in South Korea in the near future. Human remains, as archaeological data, can provide various types of information, such as the biological characteristics of past groups of people. They also provide direct data that can shed light on many aspects of cultural evolution, and discussions regarding how to properly use data from human remains excavated from archaeological sites in Korea are still in their preliminary stages. Continued developments in science and technology are expected to reveal more information than can currently be obtained from ancient human skeletal remains. To gather information on the cultures of ancient people, which is the ultimate goal of archaeology, there has to be a shared understanding that ancient human skeletal remains must be treated ethically before being viewed simply as potential sources of archaeological data. Further, to increase the value of the collected data, there is a need for a higher degree of interdisciplinary research through mutual collaboration with multiple archaeologists as well as other experts in the fields of anthropology, genetics, and biochemistry.

A Phase 1a/1b First in Human Study of PHI-101, a Potent Small Molecule Inhibitor of FLT3 in Relapsed and Refractory Acute Myeloid Leukemia

Background: The FMS-like tyrosine kinase 3 (FLT3) is mutated in approximately 30% of acute myeloid leukemia (AML) patients either by internal tandem duplication (ITD) or by point mutations in the tyrosine kinase domain (TKD). PHI-101 is a Type I FLT3 inhibitor developed to overcome resistance in AML. PHI-101 showed potent cellular activity in vitro and in vivo for both FLT3 ITD mutations and a wide variety of FLT3 point mutations in TKD. In preclinical studies utilizing primary human FLT3-ITD leukemia cells, PHI-101 showed increased anti-leukemic activity compared to gilteritinib based on increased survival in mice transplanted with these samples.The Phase 1a and Phase 1b global clinical trial with PHI-101 (NCT04842370) is currently underway to assess the overall safety and efficacy of PHI-101 in refractory and relapsed AML.Study Design and Methods: The overall design of the AML clinical trial consists of two parts, phase 1a, the dose-escalation, and phase 1b, the dose-expansion trial utilizing oral PHI-101 tablets. Up to 5 dose levels are planned for phase 1a and a single subject enrolled per dose level until the occurrence of at least one subject with more than Grade 2 toxicity according to CTCAE5.0 criteria during the 28-day evaluation period. The dose escalation will then convert to a standard 3+3 scheme, with 3 to 6 subjects per dose level cohort over the 28-day cycle. If there are no dose-limiting toxicities (DLT), dose escalation to the next higher dose levels will proceed upon the recommendation of the Safety Monitoring Committee. Subjects with FLT3 mutations or FLT3 wild-type will be enrolled in the dose-escalation cohort, and blood samples are collected for the primary endpoint pharmacokinetics (PK) and for the exploratory pharmacodynamic (PD) endpoint evaluation, including plasma inhibitory assay and biomarker analysis.Results: The Phase 1a clinical trial of PHI-101 was initiated in June 2020 at a daily dose of 40mg for level 1. As of July 31, 2021, 8 patients with relapsed or refractory AML have been enrolled in the trial, all of whom had prior anti-leukemic treatments with intensive chemotherapy, hypomethylating agents and/or other FLT3 inhibitors. To date, 5 enrolled patients were available for safety assessment at three dose levels and have not experienced any dose-limiting toxicities (DLTs) from repeating doses of the 28-day DLT-assessment window. The leukemic blasts in marrow or peripheral blood were dramatically reduced by up to 98% with one cycle (28 days). The pharmacokinetic data of plasma PHI-101 varied in a dose-proportional manner and peak plasma concentrations (Cmax) were reached between 4 and 6 hours after once-daily dosing. The pharmacodynamic evaluation by plasma inhibitory assay showed that plasma from patients receiving at daily doses of PHI-101 inhibited more than 90% of the phosphorylation of the FLT3-ITD receptor. PHI-101 was well tolerated with these dose levels. This study is currently recruiting FLT3 mutation or wild-type AML patients at multiple sites in Korea and Australia.Conclusion: PHI-101 is a next-generation FLT3 inhibitor that showed a potent anti-leukemic activity and improved efficacy in primary AML samples harboring FLT3/ITD and FLT3/TKD mutations in preclinical studies. The current analysis of this trial indicated that PHI-101 is a very effective FLT3 inhibitor for both refractory and relapsed AML patients, including those that have relapsed on other FLT3 TKI. The assessments of safety, tolerability, and PK of PHI-101 to determine the recommended dose for expansion are ongoing in the Phase 1a clinical trial. DisclosuresLee: Astellas Pharma, Inc.: Consultancy, Honoraria, Other: Advisory board; AbbVie: Honoraria, Other: Advisory board; Korean Society of Hematology: Membership on an entity's Board of Directors or advisory committees. Im: Pharos iBio Co., Ltd.: Current Employment. Nam: Pharos iBio Co., Ltd.: Current holder of individual stocks in a privately-held company. Kim: Pharos iBio Co., Ltd.: Current holder of individual stocks in a privately-held company. Han: Pharos iBio Co., Ltd.: Current holder of individual stocks in a privately-held company. Yoon: Pharos iBio Co., Ltd.: Current holder of individual stocks in a privately-held company. Small: Pharos iBio Co., Ltd.: Consultancy, Other: Scientific Advisory Board. The arrangement has been reviewed and approved by Johns Hopkins University in accordance with its conflict-of-interest policies, Research Funding; InSilico Medicine: Other: Scientific Advisory Board.

Changes in stand structure and biomass increment in a warm temperate forest at a long-term ecological research site in Korea over 17 years

Changes in stand biomass, stem density, mortality and recruitment were monitored from 2000 to 2016 at 5- or 6-year intervals of Mt. Geumsan (GMS). The GMS had 34 woody plant species and 2698 living stems (DBH ≥ 2 cm) ha−1 in 2016, with an increase in biomass from 233.80 ton ha−1 in 2000 to 282.15 ton ha−1 in 2016. The dominant species in the canopy layer was Quercus serrata, while Chamaecyparis obtusa was the dominant species in the subtree layer. During the 17 years, the biomass of Q. serrata increased from 156.35 to 198.40 ton ha−1, while the stem density of Q. serrata declined from 395 to 268 stems ha−1. In addition, the biomass of C. obtusa increased from 12.70 to 24.09 ton ha−1, and also the stem density of C. obtusa increased from 722 to 898 stems ha−1. The forest structure of GMS is expected to maintain dominance of Q. serrata, and C. obtusa is increasing. Therefore, GMS was a natural broad-leaved forest composed of Q. serrata, but natural broad-leaved species at the site are declining due to the regeneration and growth of C. obtusa, which is relatively shade-tolerant compared to other species.

Assessment of BIM Competencies and Correlation Analysis between Competencies and Career Characteristics of FAB Construction Project Participants

Currently, BIM implementation in domestic FAB construction projects is in such an early stage that they are benchmarking the BIM implementation method applied in the conventional building sector. As such, in order to enhance the usability of BIM in FAB construction projects, it is necessary to have a correct understanding of FAB construction and to apply BIM in accordance with the characteristics of FAB. This requires defining critical BIM competencies needed by the participants of FAB construction projects in undertaking their tasks as well as identifying their current level of competency possessed. Accordingly, this study defined and presented BIM competencies that reflect the characteristics of FAB through the analysis of typical tasks related to FAB construction projects. For this, project participants from three FAB construction project sites in Korea (where BIM was implemented) were recruited, and a survey was conducted on their status of competency level. Moreover, a comparative analysis was conducted focusing on the correlations between their career characteristics (‘Construction project experience’, ‘BIM-based construction project experience’, ‘FAB construction project experience’, ‘BIM-based FAB construction project experience’ and ‘Overall project experiences’) and their current level of BIM competencies. As a result, high correlations were found between BIM competencies and BIM-based FAB construction project experience for the owner group, whereas competency items related to BIM-based construction project experience showed high correlations for the designer group.

Development and Application of a Big Data Analysis-Based Procedure to Identify Concerns about Renewable Energy

To achieve carbon neutrality by 2050, Korea has been expanding its investment in renewal energy distribution and technology development. However, with this rapid expansion of renewable energy, public concern about it has grown. This study developed and used a big data analysis-based procedure to analyze the questions registered on Naver, the largest portal site in Korea, from 2008 to 2020 to identify public concern over renewable energy. The big data analysis-based procedure consisted of two steps. The first was a frequency analysis to identify the most frequently registered words. The second was to classify questions using term frequency-inverse document frequency (TF-IDF) weight and cosine similarity based on word2vec. The analysis revealed the most frequently registered words related to renewable energy, such as “solar power,” “power generation,” “energy,” and “wind power.” It also revealed the most frequently registered questions, such as those related to solar panel installation, renewable energy generation methods, and certificates. To continue expanding renewable energy, it is becoming increasingly important to understand the public’s concerns and create a method to resolve their objections to renewable energy. It is expected that the procedure in this study may provide relevant insight for the method.

Abstract CT171: Combinatorial allogeneic NK cell therapy with Pembrolizumab for cholangiocarcinoma; interim report of open label Phase1/2a study

Abstract Combinatorial allogeneic NK cell therapy with Pembrolizumab for cholangiocarcinoma; interim report of open label Phase1/2a study Background: There are several things needed to be resolved for successful efficacy when NK cell therapy is applied for solid tumor; improvement of NK cell invasion into tumor, activation and production of a large number of NK cells, etc. Basically, in human, NK cell number is relatively small compared to other immune cells such as T cell and the number becomes severely low when NK cell is obtained from cancer patients. For these reasons, allogeneic NK cell has been used for clinical studies against various cancer types. Recently, we also have finished a phase1 study of allogeneic NK cell therapy for cholangiocarcinoma, enrolling 9 patients at inoperable and no chemotherapy favorable stage due to side effects. Four of nine patients (44%) showed SD (stable disease) after six NK cell injections and no severe AE (adverse event) was found. In this following phase 2a study, to bring out immuno-synergetic effect of NK cell therapy against the inoperably advanced bile duct cancer, we have designed a combinatorial protocol with using Pembrolizumab. Methods: Enrollment of 40 bile duct cancer patients has been finished for a combinatorial study of allogeneic NK cell therapy with Pembrolizumab at two different sites in Korea (ClinicalTrials gov, NCT03937895). Patients were eligible for the enrollment when they were inoperable and no chemotherapy favorable stage due to side effects, and also when they had PD-L1-positive score. For treatment, the most favorable method for highly activated allogeneic NK cell production has been determined from our previous study, resulting that 3x106 NK cells per kg are injected for each dose along with Pembrolizumab injection. Pembrolizumab (200mg) was given every 3 weeks for up to 9 times and NK cell injection was given for up to 18 times during the maximum injection period of Pembrolizumab. Results: Six patients (pts) were first enrolled for the pilot combinatorial study, dosing 6 times of NK cells and 3 times of Pembrolizumab. The result showed no severe AE from the injections. Among the five pts finished the injections, 2 pts showed SD (Stable Disease) and continued the treatment, being enrolled into the Phase 2a in which 34 more pts were enrolled. Among the 20 pts finished 6 NK cell and 3 Pembrolizumab injections (1st RECIST), 65% of pts showed SD. When 12 NK cell and 6 Pembrolizumab injections finished (2nd RECIST), pts had 40% and 20% of SD and PR (Partial remission). Of the 3 pts at 3rd RECIST (18 NK cell and 9 Pembrolizumab), 1 and 2 pts showed SD and PR, respectively. Finding pts experienced AE, a total of 6 AEs has been reported: no treatment-related AE, one grade 3 (Encephalopathy), and five grade 1-2 with common AE. In a recent safety and efficacy study of pembrolizumab alone (10mg/kg, every 2 weeks for up to 2 years) with 28 pts of advanced bile duct cancer showing PD-L1 expression, 17% pts showed PR, 17% pts and 52% had SD and PD (progressive disease), respectively. Although our study is still ongoing, continuing the combinatorial treatment gives rise to PR, suggesting that NK cell therapy with Pembrolizumab shows an immuno-synergetic effect for the cancer. Biomarker experiments with the injected NK cells supports our finding and we will discuss this at presentation. Citation Format: Yong Yoon Chung, Seung Woo Park, Jung-Min Im, Da-Kyung Yoo, Hyo-Cheon Cheon, Jae-Eun Kim, Kyeong-Pill Lim, Eun-Hee Yang, Hye-Jin choi, Hyo-Sun Chung, Seo-Yeon Kim, Ju-Yong Lee, In-Hye Jung, Seung Min Bang, Moon Jae Chung, Sung Ill Jang, Jae Hee Cho, Hee Seung Lee, Jung Youp Park, Jung Hyun Jo. Combinatorial allogeneic NK cell therapy with Pembrolizumab for cholangiocarcinoma; interim report of open label Phase1/2a study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT171.

육아와 조부모: 온라인 카페 게시글 토픽모델 분석

In this paper, we identified key terms and latent topics in posts on online forums, called “online cafés” in Korea. We analyzed 41,699 online posts that mentioned at least one of the 70 Korean terms related to “child care” as well as one of the 67 terms related to “grandparents”. The data were posted online between 2016 and 2019 on Naver and Daum, two leading portal sites in Korea. Using topic modeling with Latent Dirichlet Allocation (LDA), we selected and named 16 topics, and then grouped them into four themes. The first theme was “grandparents and grandchildren,” which included four topics: grandparent-grandchild relationships (T1), the everyday lives of adult children and grandchildren (T2), the roles of parents and grandparents (T3), and grandparent’s leisure time (T4). The second theme was “care in early childhood” with four topics: birth order and number of children (T5), childbirth and postnatal care (T6), infant child care (T7), and attachment (T8). The third theme was “child care and support for parents” with four topics: work and child care (T9), day care and kindergarten (T10), parenting information (T11), and parenting education and counseling (T12). The last theme was “marriage and gender roles” with four topics: marital life (T13), “dok-bak-yuk-ah” (parenting solo) (T14), in-laws (T15), and divorce (T16). Our results highlight that online discussions about grandparents include a variety of topics in the context of child care, suggesting that grandparents are not only child care providers but are also actively involved in the everyday lives of their adult children and grandchildren.

Compositional Variation and Color Diversity of Glass Beads from the 4th Century Tomb Complex in Korea

This study investigated the chemical compositions and color diversity of various colored glass beads excavated from the 4th century Suchonri site in Korea. The results reveal that the compositions of the coloring materials and stabilizers contain black or white impurities, and there are clear boundaries in the weathered surfaces within the glass beads. The weathered side turned brown, the amounts of Na and K are greater, and there is a decrease in alkali elements. The fragments in blue-green beads from tomb No. 11 were identified as potash glass, whereas the rest of the samples were soda glass. Analysis of the coloration elements identified Fe and Cu in all glass beads, and it was estimated that both elements resulted in a green color. Fe was predicted to cause a brown color. The results of the study may be used not only for scientific interpretation of the relics from the Suchonri tomb complex but also as archaeological evidence that may contribute to the material characterization of the ancient glass from the Korean peninsula.

Predictors of Favorable Angiographic Outcomes After Drug-Coated Balloon Use for de novo Small Vessel Coronary Disease (DCB-ONLY).

We evaluated the angiographic parameter and clinical outcomes of drug-coated balloon (DCB) to assess the optimal angiographic criteria in de novo small vessel disease (SVD). Patients (n = 424, mean age: 64.4 ± 11.2 years, men: 69.8%) at 20 sites in Korea were prospectively enrolled. The primary end point was late luminal loss (LLL) at 9-month follow-up angiography. Secondary end points included restenosis rates, target lesion failure (TLF), and DCB-related thrombosis during the 12-month follow-up period. We included 403 patients for analysis excluding 21 patients who required bailout stenting. Baseline mean reference vessel .diameter was 2.52 ± 0.39 mm and mean minimal luminal diameter (MLD) was 0.71 ± 0.40 mm. The mean MLD was 1.54 ± 0.37 mm after DCB. Late luminal loss was -0.01 ± 0.43 mm and restenosis was noted in 26 patients (12.2%). Minimal luminal diameter >1.6 mm and %diameter stenosis (DS) <45% after DCB was associated maintenance of MLD without LLL at 9-months. Multivariate analysis demonstrated that %DS at baseline and post-MLD was associated with the restenosis. During 12-month follow-up, TLF was 2.6% including 1 cardiac death, 1 myocardial infarction, and 10 ischemia-driven target lesion revascularizations. Drug-coated balloon showed a low restenosis and lower LLL despite high in-segment DS. Post-MLD and % DS may be helpful to get optimal results in de novo SVD after DCB.

코로나로 인한 스트릿 댄스 환경 변화와 전망 탐색

This research explored the changes in the environment of the street dance scene caused by COVID-19, and tried to explore the changes in the future of the street dance scene. For this reason, we conducted case studies and conducted in-depth interview based on experiences from people involved in street dance. We selected eight research participants working at street dance sites in Korea and held in-depth interview from December 2020 to January 2021. The results derived from the analysis are as follows. First, environmental changes caused by COVID-19 created space and time constraints. In addition, online classes, battles and performances have made it difficult for dancers to make ends meet. Secondly, the scene of the street dance where the change took place was not realistic, and the online movement felt the limitations of the online system. The use of SNS is not professional, but there are opportunities for indirect participation. Online non-face-to-face systems were easier to participate in on-site, and indirect participation under government regulations provoked motivation for direct participation. Third, the post-COVID-19 street dance environment will return to offline scenes where you can feel the reality. SNS will be used as a further development method to explore the development of the street dance scene.

Pegteograstim prophylaxis for chemotherapy-induced neutropenia and febrile neutropenia: a prospective, observational, postmarketing surveillance study in Korea.

This observational study aimed to evaluate the safety and efficacy of pegteograstim prophylaxis in patients with lymphoma and solid malignancies. This study was conducted at 18 sites in Korea between November 2015 and August 2018. In total, 611 patients (female, 61.2%) with a median age of 58 (range, 18-88) years were included. Most patients had lymphomas (n = 371, 60.7%) and breast cancer (n = 230, 37.6%) and were administered R-CHOP21 (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone per 21 days) (n = 284, 46.5%) and AC (doxorubicin and cyclophosphamide) (n = 177, 29.0%). The total pegteograstim dose in the 611 patients was 14,970 mg (2495 doses), with each patient receiving an average daily dose of 6.0 mg. Neutropenia grade 4 occurred in 97 patients (15.9%), and febrile neutropenia (FN) occurred in 31 patients (5.1%). Among the 611 patients, 267 patients (43.7%) developed 882 adverse events (AEs), and 11 patients (1.8%) experienced 18 adverse drug reactions (ADRs). There were 62 patients (10.2%) who experienced 81 cases of serious adverse events (SAEs), with FN and pneumonia being the most frequent at 14 and 13 episodes, respectively, in 13 patients (2.1%). Meanwhile, 1 patient (0.2%) developed 2 episodes of serious ADRs (grade 1 and grade 2 hypotension). No safety concerns in the elderly and patients with liver and/or renal disease were identified. The prophylactic use of pegteograstim might have good overall safety and efficacy in patients with lymphomas and solid malignancies in routine clinical practice, even in those who are elderly and have liver and renal diseases.

Diversity and Communities of Fungal Endophytes from Four Pinus Species in Korea

Fungal endophytes are ubiquitous in nature. They are known as potential sources of natural products, and possible agents for biocontrol attributing to their ability to produce a repertoire of bioactive compounds. In this study, we isolated fungal endophytes from three different tissues (needle, stem and root) of four Pinus species (Pinus densiflora, Pinus koraiensis, Pnus rigida, and Pinus thunbergii) across 18 sampling sites in Korea. A total number of 5872 culturable fungal endophytes were isolated using standard culturing techniques. Molecular identification based on the sequence analyses of the internal transcribed spacer (ITS) or 28S ribosomal DNA revealed a total of 234 different fungal species. The isolated fungal endophytes belonged to Ascomycota (91.06%), Basidiomycota (5.95%) and Mucoromycota (2.97%), with 144 operational taxonomic units (OTUs) and 88 different genera. In all sampling sites, the highest species richness (S) was observed in site 1T (51 OTUs) while the lowest was observed in site 4T (27 OTUs). In terms of diversity, as measured by Shannon diversity index (H’), the sampling site 2D (H′ = 3.216) showed the highest while the lowest H’ was observed in site 2K (H’ = 2.232). Species richness (S) in three different tissues revealed that root and needle tissues are highly colonized with fungal endophytes compared to stem tissue. No significant difference was observed in the diversity of endophytes in three different tissues. Among the four Pinus species, P. thunbergii exhibited the highest species richness and diversity of fungal endophytes. Our findings also revealed that the environmental factors have no significant impact in shaping the composition of the fungal endophytes. Furthermore, FUNGuild analysis revealed three major classifications of fungal endophytes based on trophic modes namely saprotrophs, symbiotrophs, and pathotrophs in four Pinus species, with high proportions of saprotrophs and pathothrops.

Evaluation of Stabilization Capacity for Typical Amendments based on the Scenario of Heavy Metal Contaminated Sites in Korea

Evaluation of Stabilization Capacity for Typical Amendments based on the Scenario of Heavy Metal Contaminated Sites in Korea

Future extreme heat wave events using Bayesian heat wave intensity-persistence day-frequency model and their uncertainty

Heat wave events are occurring more often and over a wider area around the world, and in the coming era of global warming, their intensity will intensify and their persistence days will be longer. In this study, the relationship between the occurrence probability, intensity, and persistency days of future extreme heat wave events is explained using the concept of IDF (rainfall intensity-duration-frequency) curves for extreme rainfall events. The uncertainty of the non-stationary heat wave intensity-persistence day-frequency (HPF) model is analyzed using Bayesian inference. Non-stationary HPF curves were applied to a total of 16 future daily maximum surface air temperature ensembles projected at six major sites in Korea. From the ensemble of future climate information, it was found that the intensity of the extreme heat wave event for persistence day of 2-day estimated in 2050 would be more likely to rise in the range of 1.23–1.69 °C (under RCP 4.5) and 1.15–1.96 °C (under RCP 8.5) than that estimated in 2010. It was also found that the uncertainty resulting from parameter estimation of the HPF model was greater than the uncertainty resulting from the inter-model variability of various climate model combinations. When reflecting the uncertainty resulting from the estimation of model parameters, the 95% confidence interval of the delta change for the heat wave intensity projected in 2050 from 2010 was estimated to be 0.53–4.94 °C (under RCP 4.5) and 0.89–5.57 °C (under RCP 8.5).

Evaluation of Rainfall Erosivity Factor Estimation Using Machine and Deep Learning Models

Rainfall erosivity factor (R-factor) is one of the Universal Soil Loss Equation (USLE) input parameters that account for impacts of rainfall intensity in estimating soil loss. Although many studies have calculated the R-factor using various empirical methods or the USLE method, these methods are time-consuming and require specialized knowledge for the user. The purpose of this study is to develop machine learning models to predict the R-factor faster and more accurately than the previous methods. For this, this study calculated R-factor using 1-min interval rainfall data for improved accuracy of the target value. First, the monthly R-factors were calculated using the USLE calculation method to identify the characteristics of monthly rainfall-runoff induced erosion. In turn, machine learning models were developed to predict the R-factor using the monthly R-factors calculated at 50 sites in Korea as target values. The machine learning algorithms used for this study were Decision Tree, K-Nearest Neighbors, Multilayer Perceptron, Random Forest, Gradient Boosting, eXtreme Gradient Boost, and Deep Neural Network. As a result of the validation with 20% randomly selected data, the Deep Neural Network (DNN), among seven models, showed the greatest prediction accuracy results. The DNN developed in this study was tested for six sites in Korea to demonstrate trained model performance with Nash–Sutcliffe Efficiency (NSE) and the coefficient of determination (R2) of 0.87. This means that our findings show that DNN can be efficiently used to estimate monthly R-factor at the desired site with much less effort and time with total monthly precipitation, maximum daily precipitation, and maximum hourly precipitation data. It will be used not only to calculate soil erosion risk but also to establish soil conservation plans and identify areas at risk of soil disasters by calculating rainfall erosivity factors.